Hello All AIPMT Biology Aspirants, next topic to learn is Pancreas.

Pancreas

• It lies posterior to the greater curvature of the stomach, between the limbs of the ‘U’ shaped duodenum.
• Pancreas is an elongated and somewhat flattened organ that consists of a head, body, and tail.
• It functions as both an endocrine gland (secreting hormones into the extracellular fluid) and an exocrine gland (secreting digestive juices through the pancreatic duct to the gut lumen).
• As an endocrine gland, it secretes insulin and glucagon; hormones that help keep the blood glucose level within normal limits.
• The exocrine tissues of the pancreas secrete pancreatic juices, a host of digestive enzymes, including lipases, amylases, proteases, and nuclease.
• Exocrine cells secrete pancreatic juice into small ducts that ultimately unite to form two ducts.
• The Pancreatic duct, or Duct of Wirsung, is the larger of the two ducts.
• Pancreatic duct joins the common bile duct from the liver and gallbladder and enters the duodenum as a dilated common duct called the Hepato-pancreatic duct/Hepato-pancreatic ampulla or Ampulla of Vater.

Structure of Liver, Gall Bladder and Pancreas with their ducts

• The passage of pancreatic juice and bile through the hepato-pancreatic duct into the duodenum of the small intestine is regulated by a mass of smooth muscle known as the Sphincter of Oddi.
• The other duct of the pancreas, the Accessory duct (Duct of Santorini), leads from the pancreas and empties into the duodenum superior to the hepatopancreatic duct.

Pancreatic Islet surrounded by Acini

• Pancreas is made up of small clusters of glandular epithelial cells. About 99% of the clusters, called Acini , constitute the exocrine portion of the organ. The cells within acini secrete a mixture of fluid and digestive enzymes called pancreatic juice. The remaining 1% of the clusters, called Pancreatic islets (Islets of Langerhans) form the endocrine portion of the pancreas. These cells secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide.